TMET-48. Participant metabolic state impacts glioma PET imaging: Translational insights from [18F]DASA-10 and FDG

Abstract The metabolic state during positron emission tomography (PET) imaging can significantly influence the uptake of radiotracers and impact interpretation, especially in gliomas where glycolysis is often disrupted. This study examines how short-term fasting affects the uptake of [18F]DASA-10, a PET tracer that targets pyruvate kinase M2 (PKM2), in a preclinical glioma model. Four six-week-old rats were orthotopically implanted with C6 glioma cells and imaged using [18F]DASA-10 with PET-CT under two conditions: unrestricted access to food and after a 12-hour fast. The presence of tumors was confirmed through T2-weighted and gadolinium-enhanced T1-weighted MRI scans. Tracer uptake was quantified using two metrics: the ratio of maximum tumor uptake to maximum uptake in the contralateral healthy brain, and the ratio of average tumor uptake to average uptake in the contralateral healthy brain. Fasting significantly improved tumor-to-background contrast (p < 0.05), leading to increased [18F]DASA-10 retention in glioma regions for all subjects. These results build on prior preclinical validation of [18F]DASA-10, which showed high specificity for PKM2, low background in normal brain tissue, and strong tumor-to-brain contrast. Given the statistical significance of these findings, a larger cohort study is planned to further validate the effects of fasting. Although clinical imaging was not conducted in this study, anecdotal evidence from early-phase trials of the DASA tracer (e.g., DASA23) suggests that systemic metabolic states, such as those induced by ketogenic diets, may similarly influence the visibility of radiotracers in patients. These translational insights highlight the significance of participant preparation in metabolic PET imaging. By standardizing pre-scan conditions, such as the duration of fasting, we could enhance reproducibility, improve diagnostic accuracy, and facilitate cross-study comparisons in both experimental and clinical neuro-oncology settings.